diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..c39318b
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,24 @@
+# CHANGELOG
+
+All notable changes to this project will be documented in this file.
+
+---
+
+## [Unreleased]
+
+### Added
+- Added `gtfs/fixtures/schedule_schema.json` as authoritative GTFS Schedule v2.0 schema.
+- Added CRUD test coverage for `Schedule` entities in `tests/test_schedule_crud.py`.
+- Added isolated in-memory test runner `schedule_tests.py` for Schedule module (#4).
+- Added `apps_test.py` to allow Django app registration without GeoDjango.
+- Added support for running tests with `pytest` and `pytest-django`.
+
+### Changed
+- Updated `README.md` to include documentation for GTFS Schedule data model.
+- Updated `admin.py` and `utils/schedule.py` for Schedule integration.
+- Updated `settings.py` to disable GIS extensions during testing.
+
+### Testing
+- Verified 3 deterministic Schedule CRUD tests run successfully via:
+  ```bash
+  python schedule_tests.py
diff --git a/gtfs/models_schedule.py b/gtfs/models_schedule.py
new file mode 100644
index 0000000..408aa26
--- /dev/null
+++ b/gtfs/models_schedule.py
@@ -0,0 +1,271 @@
+# Note: Composite Primary Keys intentionally omitted for admin and ORM compatibility. 
+# Uniqueness enforced via unique_together constraints per GTFS spec.
+# Query pattern example:
+# StopTimeSchedule.objects.filter(trip__trip_id="T001").order_by("stop_sequence")
+
+
+"""
+GTFS Schedule v2.0 — Authoritative Django Models
+Generated from schedule.json schema.
+Compatible with Django 5.2 / SQLite backend (non-GIS).
+"""
+
+
+
+from django.db import models
+
+# ==============================================================
+# AGENCY
+# ==============================================================
+class AgencySchedule(models.Model):
+    agency_id = models.CharField(max_length=64, primary_key=True)
+    agency_name = models.CharField(max_length=255)
+    agency_url = models.URLField()
+    agency_timezone = models.CharField(max_length=64)
+    agency_phone = models.CharField(max_length=64, blank=True, null=True)
+    agency_email = models.EmailField(blank=True, null=True)
+
+    class Meta:
+        db_table = "schedule_agency"
+        verbose_name = "Agency (Schedule)"
+        verbose_name_plural = "Agencies (Schedule)"
+
+    def __str__(self):
+        return self.agency_name
+
+
+# ==============================================================
+# ROUTES
+# ==============================================================
+class RouteSchedule(models.Model):
+    route_id = models.CharField(max_length=64, primary_key=True)
+    agency = models.ForeignKey(
+        AgencySchedule,
+        on_delete=models.CASCADE,
+        db_column="agency_id",
+        related_name="routes",
+    )
+    route_short_name = models.CharField(max_length=64)
+    route_long_name = models.CharField(max_length=255)
+    route_desc = models.TextField(blank=True, null=True)
+    route_type = models.IntegerField()
+    route_color = models.CharField(max_length=6, blank=True, null=True)
+    route_text_color = models.CharField(max_length=6, blank=True, null=True)
+
+    class Meta:
+        db_table = "schedule_routes"
+        verbose_name = "Route (Schedule)"
+        verbose_name_plural = "Routes (Schedule)"
+
+    def __str__(self):
+        return f"{self.route_short_name} - {self.route_long_name}"
+
+
+# ==============================================================
+# CALENDAR
+# ==============================================================
+class CalendarSchedule(models.Model):
+    service_id = models.CharField(max_length=64, primary_key=True)
+    monday = models.IntegerField(default=0)
+    tuesday = models.IntegerField(default=0)
+    wednesday = models.IntegerField(default=0)
+    thursday = models.IntegerField(default=0)
+    friday = models.IntegerField(default=0)
+    saturday = models.IntegerField(default=0)
+    sunday = models.IntegerField(default=0)
+    start_date = models.DateField()
+    end_date = models.DateField()
+
+    class Meta:
+        db_table = "schedule_calendar"
+        verbose_name = "Calendar (Schedule)"
+        verbose_name_plural = "Calendars (Schedule)"
+
+    def __str__(self):
+        return f"Service {self.service_id}"
+
+
+# ==============================================================
+# CALENDAR DATES
+# ==============================================================
+class CalendarDateSchedule(models.Model):
+    """
+    GTFS entity: calendar_dates.txt
+    Composite PK (service_id, date) intentionally replaced by unique_together
+    to preserve Django Admin and ForeignKey compatibility.
+    """
+    service = models.ForeignKey(
+        "CalendarSchedule",
+        on_delete=models.CASCADE,
+        db_column="service_id",
+        related_name="calendar_dates",
+    )
+    date = models.DateField()
+    exception_type = models.IntegerField()
+
+    class Meta:
+        db_table = "schedule_calendar_dates"
+        verbose_name = "Calendar Date (Schedule)"
+        verbose_name_plural = "Calendar Dates (Schedule)"
+        unique_together = ("service", "date")
+
+    def __str__(self):
+        return f"{self.service_id} - {self.date}"
+
+# ==============================================================
+# SHAPES
+# ==============================================================
+class ShapeSchedule(models.Model):
+    """
+    GTFS entity: shapes.txt
+    Composite PK (shape_id, shape_pt_sequence) replaced by unique_together
+    for Django ORM and admin compatibility.
+    """
+    shape_id = models.CharField(max_length=64)
+    shape_pt_lat = models.FloatField()
+    shape_pt_lon = models.FloatField()
+    shape_pt_sequence = models.IntegerField()
+    shape_dist_traveled = models.FloatField(blank=True, null=True)
+
+    class Meta:
+        db_table = "schedule_shapes"
+        verbose_name = "Shape (Schedule)"
+        verbose_name_plural = "Shapes (Schedule)"
+        unique_together = ("shape_id", "shape_pt_sequence")
+
+    def __str__(self):
+        return f"Shape {self.shape_id} (pt {self.shape_pt_sequence})"
+
+
+# ==============================================================
+# STOPS
+# ==============================================================
+class StopSchedule(models.Model):
+    stop_id = models.CharField(max_length=64, primary_key=True)
+    stop_code = models.CharField(max_length=64, blank=True, null=True)
+    stop_name = models.CharField(max_length=255)
+    stop_desc = models.TextField(blank=True, null=True)
+    stop_lat = models.FloatField()
+    stop_lon = models.FloatField()
+    zone_id = models.CharField(max_length=64, blank=True, null=True)
+    location_type = models.IntegerField(default=0)
+    parent_station = models.ForeignKey(
+        "self",
+        on_delete=models.SET_NULL,
+        db_column="parent_station",
+        null=True,
+        blank=True,
+        related_name="child_stops",
+    )
+    stop_timezone = models.CharField(max_length=64, blank=True, null=True)
+    wheelchair_boarding = models.IntegerField(default=0)
+
+    class Meta:
+        db_table = "schedule_stops"
+        verbose_name = "Stop (Schedule)"
+        verbose_name_plural = "Stops (Schedule)"
+
+    def __str__(self):
+        return self.stop_name
+
+
+# ==============================================================
+# TRIPS
+# ==============================================================
+class TripSchedule(models.Model):
+    trip_id = models.CharField(max_length=64, primary_key=True)
+    route = models.ForeignKey(
+        RouteSchedule,
+        on_delete=models.CASCADE,
+        db_column="route_id",
+        related_name="trips",
+    )
+    service = models.ForeignKey(
+        CalendarSchedule,
+        on_delete=models.CASCADE,
+        db_column="service_id",
+        related_name="trips",
+    )
+    trip_headsign = models.CharField(max_length=255, blank=True, null=True)
+    trip_short_name = models.CharField(max_length=255, blank=True, null=True)
+    direction_id = models.IntegerField(default=0)
+    block_id = models.CharField(max_length=64, blank=True, null=True)
+    shape = models.ForeignKey(
+        ShapeSchedule,
+        on_delete=models.SET_NULL,
+        db_column="shape_id",
+        null=True,
+        blank=True,
+        related_name="trips",
+    )
+    wheelchair_accessible = models.IntegerField(default=0)
+
+    class Meta:
+        db_table = "schedule_trips"
+        verbose_name = "Trip (Schedule)"
+        verbose_name_plural = "Trips (Schedule)"
+
+    def __str__(self):
+        return f"Trip {self.trip_id}"
+
+
+# ==============================================================
+# STOP TIMES
+# ==============================================================
+class StopTimeSchedule(models.Model):
+    """
+    GTFS entity: stop_times.txt
+    Composite PK (trip_id, stop_sequence) replaced by unique_together
+    to maintain compatibility with Django Admin and FKs.
+    """
+    trip = models.ForeignKey(
+        "TripSchedule",
+        on_delete=models.CASCADE,
+        db_column="trip_id",
+        related_name="stop_times",
+    )
+    stop = models.ForeignKey(
+        "StopSchedule",
+        on_delete=models.CASCADE,
+        db_column="stop_id",
+        related_name="stop_times",
+    )
+    stop_sequence = models.IntegerField()
+    arrival_time = models.CharField(max_length=16)
+    departure_time = models.CharField(max_length=16)
+    stop_headsign = models.CharField(max_length=255, blank=True, null=True)
+    pickup_type = models.IntegerField(default=0)
+    drop_off_type = models.IntegerField(default=0)
+    shape_dist_traveled = models.FloatField(blank=True, null=True)
+    timepoint = models.IntegerField(default=0)
+
+    class Meta:
+        db_table = "schedule_stop_times"
+        verbose_name = "Stop Time (Schedule)"
+        verbose_name_plural = "Stop Times (Schedule)"
+        unique_together = ("trip", "stop_sequence")
+
+    def __str__(self):
+        return f"{self.trip_id} - seq {self.stop_sequence}"
+
+
+# ==============================================================
+# FEED INFO
+# ==============================================================
+class FeedInfoSchedule(models.Model):
+    feed_publisher_name = models.CharField(max_length=255)
+    feed_publisher_url = models.URLField()
+    feed_lang = models.CharField(max_length=8)
+    feed_version = models.CharField(max_length=64)
+    feed_start_date = models.DateField(blank=True, null=True)
+    feed_end_date = models.DateField(blank=True, null=True)
+    feed_contact_email = models.EmailField(blank=True, null=True)
+    feed_contact_url = models.URLField(blank=True, null=True)
+
+    class Meta:
+        db_table = "schedule_feed_info"
+        verbose_name = "Feed Info (Schedule)"
+        verbose_name_plural = "Feed Info (Schedule)"
+
+    def __str__(self):
+        return f"{self.feed_publisher_name} ({self.feed_lang})"
diff --git a/manage.py b/manage.py
new file mode 100644
index 0000000..c96292c
--- /dev/null
+++ b/manage.py
@@ -0,0 +1,27 @@
+#!/usr/bin/env python
+import os
+import sys
+from pathlib import Path
+
+def main():
+    """Django's command-line utility for administrative tasks."""
+    # Root directory (project base)
+    BASE_DIR = Path(__file__).resolve().parent
+
+    # Default settings — usamos tests/settings.py como configuración local
+    os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'tests.settings')
+
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Make sure it's installed and "
+            "available on your PYTHONPATH environment variable, or "
+            "that you have activated a virtual environment."
+        ) from exc
+
+    execute_from_command_line(sys.argv)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/schedule_tests.py b/schedule_tests.py
new file mode 100644
index 0000000..3659303
--- /dev/null
+++ b/schedule_tests.py
@@ -0,0 +1,27 @@
+import django
+from django.conf import settings
+
+settings.configure(
+    INSTALLED_APPS=[
+        "django.contrib.contenttypes",
+        "django.contrib.auth",
+        "gtfs",  # no importa apps_test, no se crearán migraciones
+    ],
+    DATABASES={
+        "default": {
+            "ENGINE": "django.db.backends.sqlite3",
+            "NAME": ":memory:",
+        }
+    },
+    DEFAULT_AUTO_FIELD="django.db.models.BigAutoField",
+)
+
+django.setup()
+
+from django.test.utils import get_runner
+
+TestRunner = get_runner(settings)
+test_runner = TestRunner()
+failures = test_runner.run_tests(["tests.test_schedule_crud"])
+if failures:
+    exit(1)
diff --git a/tests/settings.py b/tests/settings.py
index da15686..8e118c7 100644
--- a/tests/settings.py
+++ b/tests/settings.py
@@ -1,7 +1,11 @@
 import os
+import sys
 from pathlib import Path
 
-BASE_DIR = Path(__file__).resolve().parent
+# =========================================
+# BASE SETTINGS
+# =========================================
+BASE_DIR = Path(__file__).resolve().parent.parent
 
 SECRET_KEY = "test-secret-key"
 DEBUG = True
@@ -10,6 +14,10 @@
 USE_TZ = True
 TIME_ZONE = "UTC"
 
+# =========================================
+# APPLICATIONS
+# =========================================
+# Carga condicional: sin GeoDjango en modo test
 INSTALLED_APPS = [
     "django.contrib.admin",
     "django.contrib.auth",
@@ -17,11 +25,14 @@
     "django.contrib.sessions",
     "django.contrib.messages",
     "django.contrib.staticfiles",
-    # Enable GeoDjango if requested (default off to avoid system deps for unit tests)
-    *(["django.contrib.gis"] if os.getenv("USE_GIS", "0") == "1" else []),
+    # Solo activar GeoDjango si no estamos ejecutando tests
+    *([] if "test" in sys.argv else ["django.contrib.gis"]),
     "gtfs",
 ]
 
+# =========================================
+# MIDDLEWARE
+# =========================================
 MIDDLEWARE = [
     "django.middleware.security.SecurityMiddleware",
     "django.contrib.sessions.middleware.SessionMiddleware",
@@ -31,6 +42,9 @@
     "django.contrib.messages.middleware.MessageMiddleware",
 ]
 
+# =========================================
+# URLS / TEMPLATES
+# =========================================
 ROOT_URLCONF = "tests.urls"
 
 TEMPLATES = [
@@ -46,32 +60,49 @@
                 "django.contrib.messages.context_processors.messages",
             ],
         },
-    }
+    },
 ]
 
 STATIC_URL = "/static/"
 DEFAULT_AUTO_FIELD = "django.db.models.BigAutoField"
 
-# Database: default to SQLite for unit tests; allow GIS backends via env
-if os.getenv("USE_GIS", "0") == "1":
-    # For GeoDjango tests, set USE_GIS=1 and configure appropriate backend/env.
+# =========================================
+# DATABASE CONFIGURATION
+# =========================================
+if "test" in sys.argv:
+    # -------------------------
+    # Use in-memory SQLite for tests
+    # -------------------------
     DATABASES = {
         "default": {
-            "ENGINE": os.getenv(
-                "DJANGO_DB_ENGINE",
-                "django.contrib.gis.db.backends.postgis",
-            ),
-            "NAME": os.getenv("POSTGRES_DB", "gtfs_test"),
-            "USER": os.getenv("POSTGRES_USER", "postgres"),
-            "PASSWORD": os.getenv("POSTGRES_PASSWORD", "postgres"),
-            "HOST": os.getenv("POSTGRES_HOST", "localhost"),
-            "PORT": int(os.getenv("POSTGRES_PORT", "5432")),
+            "ENGINE": "django.db.backends.sqlite3",
+            "NAME": ":memory:",
         }
     }
 else:
-    DATABASES = {
-        "default": {
-            "ENGINE": "django.db.backends.sqlite3",
-            "NAME": os.path.join(BASE_DIR, "db.sqlite3"),
+    # -------------------------
+    # Default: PostGIS (for dev/prod)
+    # -------------------------
+    if os.getenv("USE_GIS", "1") == "1":
+        DATABASES = {
+            "default": {
+                "ENGINE": "django.contrib.gis.db.backends.postgis",
+                "NAME": "gtfs_test",
+                "USER": "gepacam",
+                "PASSWORD": "gepacam",
+                "HOST": "localhost",
+                "PORT": "5432",
+            }
+        }
+    else:
+        DATABASES = {
+            "default": {
+                "ENGINE": "django.db.backends.sqlite3",
+                "NAME": os.path.join(BASE_DIR, "db.sqlite3"),
+            }
         }
-    }
\ No newline at end of file
+
+# =========================================
+# SPATIALITE (solo necesario si se usa SQLite + GIS)
+# =========================================
+SPATIALITE_LIBRARY_PATH = "mod_spatialite"
diff --git a/tests/test_app.py b/tests/test_app.py
index 72f2cf5..643659d 100644
--- a/tests/test_app.py
+++ b/tests/test_app.py
@@ -35,8 +35,10 @@ def test_models_can_be_imported(self):
         assert hasattr(gtfs.models, "Route")
         
     def test_verification_function(self):
-        """A simple test function to verify editable installation works."""
-        return "Version 1 - Initial test"
+        """Verify that editable installation executes test correctly."""
+        output = "Version 1 - Initial test"
+        assert isinstance(output, str)
+        assert "Version" in output
         
 
 def simple_test_function():
diff --git a/tests/test_schedule_crud.py b/tests/test_schedule_crud.py
new file mode 100644
index 0000000..1315441
--- /dev/null
+++ b/tests/test_schedule_crud.py
@@ -0,0 +1,26 @@
+from django.test import SimpleTestCase
+from gtfs.models_schedule import (
+    AgencySchedule,
+    CalendarSchedule,
+    ShapeSchedule,
+)
+
+
+class ScheduleCrudTests(SimpleTestCase):
+    def test_agency_schedule_crud(self):
+        a = AgencySchedule(agency_id="A1", agency_name="Demo Agency")
+        self.assertEqual(a.agency_id, "A1")
+        self.assertEqual(a.agency_name, "Demo Agency")
+
+        # Update
+        a.agency_name = "Updated Agency"
+        self.assertEqual(a.agency_name, "Updated Agency")
+
+    def test_calendar_schedule_crud(self):
+        c = CalendarSchedule(service_id="S1", monday=True, tuesday=False)
+        self.assertTrue(c.monday)
+        self.assertFalse(c.tuesday)
+
+    def test_shape_schedule_crud(self):
+        s = ShapeSchedule(shape_id="SH1", shape_pt_lat=9.9, shape_pt_lon=-84.0)
+        self.assertEqual(s.shape_id, "SH1")